libeap/src/ap/ndisc_snoop.c

   1 /*
   2  * Neighbor Discovery snooping for Proxy ARP
   3  * Copyright (c) 2014, Qualcomm Atheros, Inc.
   4  *
   5  * This software may be distributed under the terms of the BSD license.
   6  * See README for more details.
   7  */
   8
   9 #include "utils/includes.h"
  10 #include <netinet/ip6.h>
  11 #include <netinet/icmp6.h>
  12
  13 #include "utils/common.h"
  14 #include "l2_packet/l2_packet.h"
  15 #include "hostapd.h"
  16 #include "sta_info.h"
  17 #include "ap_drv_ops.h"
  18 #include "list.h"
  19 #include "x_snoop.h"
  20 #include "ndisc_snoop.h"
  21
  22 struct ip6addr {
  23         struct in6_addr addr;
  24         struct dl_list list;
  25 };
  26
  27 struct icmpv6_ndmsg {
  28         struct ip6_hdr ipv6h;
  29         struct icmp6_hdr icmp6h;
  30         struct in6_addr target_addr;
  31         u8 opt_type;
  32         u8 len;
  33         u8 opt_lladdr[0];
  34 } STRUCT_PACKED;
  35
  36 #define ROUTER_ADVERTISEMENT    134
  37 #define NEIGHBOR_SOLICITATION   135
  38 #define NEIGHBOR_ADVERTISEMENT  136
  39 #define SOURCE_LL_ADDR          1
  40
  41 static int sta_ip6addr_add(struct sta_info *sta, struct in6_addr *addr)
  42 {
  43         struct ip6addr *ip6addr;
  44
  45         ip6addr = os_zalloc(sizeof(*ip6addr));
  46         if (!ip6addr)
  47                 return -1;
  48
  49         os_memcpy(&ip6addr->addr, addr, sizeof(*addr));
  50
  51         dl_list_add_tail(&sta->ip6addr, &ip6addr->list);
  52
  53         return 0;
  54 }
  55
  56
  57 void sta_ip6addr_del(struct hostapd_data *hapd, struct sta_info *sta)
  58 {
  59         struct ip6addr *ip6addr, *prev;
  60
  61         dl_list_for_each_safe(ip6addr, prev, &sta->ip6addr, struct ip6addr,
  62                               list) {
  63                 hostapd_drv_br_delete_ip_neigh(hapd, 6, (u8 *) &ip6addr->addr);
  64                 os_free(ip6addr);
  65         }
  66 }
  67
  68
  69 static int sta_has_ip6addr(struct sta_info *sta, struct in6_addr *addr)
  70 {
  71         struct ip6addr *ip6addr;
  72
  73         dl_list_for_each(ip6addr, &sta->ip6addr, struct ip6addr, list) {
  74                 if (ip6addr->addr.s6_addr32[0] == addr->s6_addr32[0] &&
  75                     ip6addr->addr.s6_addr32[1] == addr->s6_addr32[1] &&
  76                     ip6addr->addr.s6_addr32[2] == addr->s6_addr32[2] &&
  77                     ip6addr->addr.s6_addr32[3] == addr->s6_addr32[3])
  78                         return 1;
  79         }
  80
  81         return 0;
  82 }
  83
  84
  85 static void ucast_to_stas(struct hostapd_data *hapd, const u8 *buf, size_t len)
  86 {
  87         struct sta_info *sta;
  88
  89         for (sta = hapd->sta_list; sta; sta = sta->next) {
  90                 if (!(sta->flags & WLAN_STA_AUTHORIZED))
  91                         continue;
  92                 x_snoop_mcast_to_ucast_convert_send(hapd, sta, (u8 *) buf, len);
  93         }
  94 }
  95
  96
  97 static void handle_ndisc(void *ctx, const u8 *src_addr, const u8 *buf,
  98                          size_t len)
  99 {
 100         struct hostapd_data *hapd = ctx;
 101         struct icmpv6_ndmsg *msg;
 102         struct in6_addr saddr;
 103         struct sta_info *sta;
 104         int res;
 105         char addrtxt[INET6_ADDRSTRLEN + 1];
 106
 107         if (len < ETH_HLEN + sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr))
 108                 return;
 109         msg = (struct icmpv6_ndmsg *) &buf[ETH_HLEN];
 110         switch (msg->icmp6h.icmp6_type) {
 111         case NEIGHBOR_SOLICITATION:
 112                 if (len < ETH_HLEN + sizeof(*msg))
 113                         return;
 114                 if (msg->opt_type != SOURCE_LL_ADDR)
 115                         return;
 116
 117                 /*
 118                  * IPv6 header may not be 32-bit aligned in the buffer, so use
 119                  * a local copy to avoid unaligned reads.
 120                  */
 121                 os_memcpy(&saddr, &msg->ipv6h.ip6_src, sizeof(saddr));
 122                 if (!(saddr.s6_addr32[0] == 0 && saddr.s6_addr32[1] == 0 &&
 123                       saddr.s6_addr32[2] == 0 && saddr.s6_addr32[3] == 0)) {
 124                         if (len < ETH_HLEN + sizeof(*msg) + ETH_ALEN)
 125                                 return;
 126                         sta = ap_get_sta(hapd, msg->opt_lladdr);
 127                         if (!sta)
 128                                 return;
 129
 130                         if (sta_has_ip6addr(sta, &saddr))
 131                                 return;
 132
 133                         if (inet_ntop(AF_INET6, &saddr, addrtxt,
 134                                       sizeof(addrtxt)) == NULL)
 135                                 addrtxt[0] = '\0';
 136                         wpa_printf(MSG_DEBUG, "ndisc_snoop: Learned new IPv6 address %s for "
 137                                    MACSTR, addrtxt, MAC2STR(sta->addr));
 138                         hostapd_drv_br_delete_ip_neigh(hapd, 6, (u8 *) &saddr);
 139                         res = hostapd_drv_br_add_ip_neigh(hapd, 6,
 140                                                           (u8 *) &saddr,
 141                                                           128, sta->addr);
 142                         if (res) {
 143                                 wpa_printf(MSG_ERROR,
 144                                            "ndisc_snoop: Adding ip neigh failed: %d",
 145                                            res);
 146                                 return;
 147                         }
 148
 149                         if (sta_ip6addr_add(sta, &saddr))
 150                                 return;
 151                 }
 152                 break;
 153         case ROUTER_ADVERTISEMENT:
 154                 if (hapd->conf->disable_dgaf)
 155                         ucast_to_stas(hapd, buf, len);
 156                 break;
 157         case NEIGHBOR_ADVERTISEMENT:
 158                 if (hapd->conf->na_mcast_to_ucast)
 159                         ucast_to_stas(hapd, buf, len);
 160                 break;
 161         default:
 162                 break;
 163         }
 164 }
 165
 166
 167 int ndisc_snoop_init(struct hostapd_data *hapd)
 168 {
 169         hapd->sock_ndisc = x_snoop_get_l2_packet(hapd, handle_ndisc,
 170                                                  L2_PACKET_FILTER_NDISC);
 171         if (hapd->sock_ndisc == NULL) {
 172                 wpa_printf(MSG_DEBUG,
 173                            "ndisc_snoop: Failed to initialize L2 packet processing for NDISC packets: %s",
 174                            strerror(errno));
 175                 return -1;
 176         }
 177
 178         return 0;
 179 }
 180
 181
 182 void ndisc_snoop_deinit(struct hostapd_data *hapd)
 183 {
 184         l2_packet_deinit(hapd->sock_ndisc);
 185 }